include iszero_simps in semiring_norm just once (they are already included in rel_simps)
include iszero_simps in semiring_norm just once (they are already included in rel_simps)

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle